Forehearth for molten glass



3 Sheets-Sheet 3 v. MULHOLLAND FV'OREHEARTH FOR MOLTEN GLASS Filed June 14, I1930 March 7, 1933.

f fave/z tor: 067395Z Wal/a;

Patented l l7, l93

` UNITED STATES rATENr ol-"Ficle:

vRRGIL NULHCLLAND, or wEsT'mRTroRD, CONNECTICUT, AssIeNoR To HARTFORD- RMPIRR Company, or HARTFORD, CONNECTICUT, A conroRATIoN lor v:liarinwniiia FOBEHEABTH FOR HOLTEN GLASS Application "mea v.rum 14,

This invention relates to a forehearth for receiving molten` glass from a melting furnace and for conducting such glass 1n a stream to a feed spout, gathering -basin or other place at which g ass is to be fed toward the plalce at which glass is to be removed and the glass maintained at a desirable temperature when thesame has been attained. I

It is well known that the glass at the sides and bottom of a stream flowing from a melting furnace'along a forehearth channel or like conduit tends to -flow more slowly4 and to become cooler than the glass of the lmiddle portion of such stream. This condition is knownl as channeling and is objectionable in that it may preclude theA removal at the delivery end of the forehearth channel or conduit of yglass suiiciently uniform inv temperature, viscosity and condition, to per? mit the 'use of such glass in the manner and for the purpose intended, as for fabrication into satisfactory articles of glassware. The

glass at the side and bottom portions of the stream niay become practically stationary and may devitrify' or become cordy when channeling exists. Portions of the devitrified 'glass may Slough off and be entrained with the relatively hot or fluid glass vofthe median portion of the stream. This condition of course is unsatisfactory.

In view of the tendency of the glass stream flowing from the melting furnace along the forehearth, channel, to channel it is desirable that provision be made to regulably control the temperature of the glass stream so as .to obtain a substantially uniform rate of How and a substantially uniform proper temperature and viscosity condition in the glass throughout the cross section, of the stream before such glass reaches the place at which glass isI to be fed through an out- '1 93o. semi No. 461,132.

let ingmold charges or otherwise removed for I fabrication into articles of glassware.

It has heretofore been proposed to apply heat locally to the glass of the side or border portionsvof the stream and to regulably control the amount of heat radiation from the middle portion of the stream with a view`to decreasing the rate of flow of and cooling of the glass of the middle portion of the stream and at the same time preventing substantial decrease of flow and undue lowering of temperature of the glass of the side portions of the stream, to the end that a condition of substantially uniform. temperature and viscosity throughout the -cross section of the stream'may be established.A The prior copending application ofthe present appli'- cant and Alfred R. Hunter, Serial N 0.401,-

831, iiled Oct. 23, 1929, discloses and claims a forehearth having heat applying and radiation controlling means of the t pe just described for the purpose stated. he present applicationdicloses many features of improvement over the disclosure of the prior copending application, Serial No. 401,831, and over other prior forehearth structures in which regulable control of the temperaturelandcondition of the glass has been at'- t'empted. Many ,'of such features of im# provement will be hereinafter particularly pointed out and others will become apparent from the following description.v

An object of the present inventionlis to provide an improved forehearth construction in which provision is made for bringing the glass of a stream from' the melting tank to the desired temperature and viscosity -and for stabilizing such condition as the liquid fuel or gaseous-fuel burners may be l employed without material change of the forehearth structure.

A further objectof the invention is the provision in a forehearth having a longitudinal slot or opening at its topv and adjustable covers for controlling radiation of heat from the glass through such slot or opening of improved means for adjusting such covers quickly and conveniently to control regulably and accurately the amount of said radiation.

A further object of the invention is to pro- 'i vide in a forehearth of the character described improved means for obtaining practically complete combustion of liquid' fuel in `a spacein communication with the glass conducting channel'and for directing the llame resulting from such combustion onto the glass without subjecting the glass to the harmful action of unconsumed particles of the combustible mixture.

A further object ofthe invention is the provision of a forehearth having improved means for effecting the desired regulation of temperature and viscosity throughout the cross section of the stream as the glass flows from the melting 'furnace along a portion of the iow channel and for thereafter equalizing the temperature condition in the glass glass iiows along a further portion of the flow channel to the place at which glass is to be fed through an outlet or otherwise removed.

. A further object of the invention is the provision of improved means for regulably in a portion of the forehearth.

Other objects and advantages of the invention will become apparent from the following description when it is considered in conjunction with the accompanying drawings, in which:

Figure l is a longitudinal .yertical section throughk a forehearth equipped with improvements embodying the invention, a portion of the side wall above the forehearth channel being broken away and certain operating and supporting parts of the complete forehearth structure being omitted, the view being approximately alongv the line indicated at 1-1 in Fig. 2;

Fig. 2 is a transverse vertical section through the forehearth structure, the View incomes llaeing approximately along the "line i2-2 of 4ig. 1; v

Fig. 3 is a plan sectional view of the outer portion of the forehearth structure, the section having been taken approximately along the line 3-3 of Fig. .1;

Fig. 4 is a relatlvely enlarged faceA view of a burner assembly and 'a support therefor at the rear end of one of the side combustion chambers of the outer end portion of the forehearth; and v Fig. 5 is a vertical section through the burner assembly of Fi 4, the View being substantially along the ine 5-5 of Fig. 4.

In'carrying out the invention, the improved forehearth may be disposed appurtenant to a glass melting tank so that glass from such tank will flow in a stream into andI along the forehearth channel. forehearth channel is suitably supported and insulated so that radiation of heat through the walls of the channel will be reduced'to a minimum. At the outer end of `the forehearth channel, a bowl or spout having a bottom delivery outlet may be pro- This aoI

vided as an extension of the forehearth. Al

gathering basin for suction gathering receptacles or other suitable known means for holdingglass to permit removal of portions thereof may be provided inlieu of the feed bowl dnspout.

The upper structure of the forehearth preferably is formed for cooperation with said channel to provide a real` enclosed temperature regulating or conditionin chamber extending for part of the length o the forehearth and an enclosed temperature equalizing and stabilizing chamber extending for the remainder of the length of the forehearth and including the space above the glass in the feed bowl or spout when the forehearth is equipped with the latter. A sting-out space preferably is provided at the rear end of the forehearth between thel .u per forehearth structure and the adjacent wall of the melting furnace sovthat the temperature above the glass in the rear'temperatureregulating or conditioning chamber will not be materially affected by heat gases from the space above the glass4 in the furnace. Also, the space above the glass in the front chamber preferably'is practically separated from the space above the glass in the rear chamber.

.lt is usual in practica-l glass working op'- erations for the temperature ofthe glass entering the iiowl channel of the forehearth to be higher than that desired for the glass to be `fed or removed. Lowering of' the temperature of the glass at the middle of the stream and controlled application of heat to the glass-at the sides of the stream the glass vof the side AA longitudinal slot or opening is provided in the top ofthe forehearth a such slot of heat from the underlying glass of the stream may be controlled by pairs of cooperative pivoted cover. sections' or shutters. The shutters of'each'pair preferabl are opened and closedsimultaneously an to the same extent by .maipulation of a single operating member.

Combustion chambers or provided at the sides of the rear or conditioning chamber. -The vside combustion chambers or firing spaces may extend for-` practically the entire length of the rear chamber. Bafles are arranged 'at the inner sides of such combustion chambers, preferably outwardly of the space above the glass combustion chambers, the --positions- `y`and pharacters of the bailles, the burners, and

the inlet for the air around the burner tips' are selected with relation tolone another and with respect tothe position of the narrow passages for applying 'flame to the glass so that practically complete combustion will be produced .at la relatively short distance from theI burner tips, even when liquid fuel is used, and no u nconsumed fuel'particles are projected into contact with the glass.'

Improved means are provided for controlling draft and temperature conditions in the space above thel glass in the stabilv izing chamber and above the` glass at the y place at which glass is to be fed or otherwise removed. Such improved means preferably includes burners at the rear of the side combustion portions of the stabilizing chamber for directing lamesforwardl'y and inwardly along the surface of the glass but also means for regulably controlling the admission of air around the burners so that combustion will be complete before contact of any unconsumed particles of combustible mixture with the glass and so that the velocity and extent of projection of flame from the burners in the stabilizing chamber may be regulably controlled. y

Damper controlled stacks also may be provided atboth the front and rear of the stabilizi'ng chamber for aiding in controlling ove the rear or conditioning chamber. Radiation through firing spaces are the temperature' and `draft conditions therein. v

Referring now to thel drawings, a forehearth channel, generallyr indicated at .1, .is show n ap urtenant lto awall 2 of a melting' urnace, not shown. The orehearth channel is made of Suitable refractory l material and is suitabl su ported and insulated, as by the fire nel; 3, the metallic casing 4 and the frame structure 5, Fig. 1. The arrangement is such that the forehearth channel will be maintained continuously inl proper position to receive molten glass in a stream from an outlet 6 of the glass meltin furnace. The particular means for insu ating and supporting the forehearth channel may vary considerably in structural features from that shown in the drawings. For example, such. su porting and insulating structure may be su stantially the same as Athat of the well known Hartford single feeder, a disclosure of vwhich may be found las in Patent No. '1,760,254, granted- May 27,

1930, to Karl E. Peiler, assignor to the Hartford-Empire Company.

A feed spout 7', having a bottom discharge outlet 8, is shown in Fig. l at the outer end of the forehearth channel 1, as an extension of the latter, and is suitably secured in position in anyv suitablelmown manner. The feed bowl 7 is shown as being provided with granular insulating-material 9, retained in place by an. outercasing 10. The latter may be attached to the supporting casing and'frame structure of the forehearth prop- The glass from the furnace outlet 6 flows in a stream, indicated at 11, along the forehearth channel to the feed spout so as to submergethe outletl 8 vin the latter. The discharge of glass through the outlet 8 may be controlled by an implement 12 which may be reciprocated in the glass in Working alignment with the outlet. The flow of glass to the outletmay be controlled by a tubular member 13 which surrounds the implement 12 and may be adjusted vertically and/or rotated in the manner and for the purposes now Well known in the glass working art.

through a suitable opening that is provided midway of the distance from the outlet in the furnace to the' place at which theI 'glass is to be fed or vremoved at the outer end of the forehearth channel.- A rear transverse refractory wall 16 spans the rear end of the forehearth channel and may be spaced from the adjacent wall of the furnace, as at 17 sufficiently to permit a sting-out of heated gases from the space above the glass 11'5 y The implements 12` and 13 depend in the furnace. The refractory members i A15 and 16 have tlieir lower edges spaced but f slightly, if at all, above the level ofthe glass bined supporting and flame distributing blocks 19, 20, 21, 22 and 23, Fig. 1. The temperature regulating or conditioning chamber referred to, indicated at 24 in Fig. 2, is closed more or less at its top by a vlongitudinal series of pairs of hingedrefractory cover sections or shutters 25.

Extending along the'sides of the condil tioning chamber ,24` are side firing chambers or combustion spaces 26. These side combustion chambers 26 have refvactory top .'walls 27, the upper` faces of which preferably are iush with the upper surfaces of the refractory-members 18. The top walls 27 are suitably supported, as by refractory blocks, such as indicated at 28 in Fig. 3; shoulders 29 on portions of the members 18, as shown in Fig. 2; end walls of the y said combustion spaces, vsuch as indicated at 3() in Fig. 3; and outer side walls of such spaces, as indicated at 31 in Figs. l and 3.

The top walls 27 of the side combustion spaces cooperate with the inner walls 18 of such combustion spaces to support substantially U-shaped holders 32, Fig. 2, in which l the outer portions of the shutters 25 are secured, as by means of the clamping devices 33. The web portions of such holders are provided at their bottoms with curved outwardlyfextending portions; constituting rockers 34, on which the holders and the shutters may rock about the axes of fulcrum rods 35. The fulcrum rods 35 may be secured to any' suitable; parts of the general frame work structure. When the lower flanges'of the substantially U-shaped holdersrest flatly on thegsupporting walls of the side portions of the forehearth structure, the shutters of each pair will be disposed horizontally, as shown in Fig. 2. This is the closed position of suchy shutters, and

in such closed position, their adjacent ends may be spaced slightly apart, as indicated at 36, to permit escape of heated gases from the conditioning chamber.

The means for opening and closing the shutters of each pair simultaneously will' now be described. Such'means comprise oppositely extending arms 37 secured at their inner endsto the upper flanges of the shutter holders and extending outwardly beyond the side walls of the forehearth.

:Lacasse Flexible cables 3,8 and 39, respectively, are

lshown as being attached at their upper ends to the outer ends of the arms 37 for the shutters of each pair. These cables may be chains, as shown, or may have any other suitable construction. The cable 38 extends downwardly along the adjacent side of the known construction, such as an assembly that may be obtained commercially as an entity. Such unit may be secured adjustably as shown to the frame work structure of the forehearth. `The cable 39 extends 38 and 39 thereon in thesame direction and thereby to rock the shutters 25 of one pair upwardly about the axes of the fulcrum rod 35. This will enlarge the space between the adjacent ends of the "shutters ofthat pair and also willincreasev the height of the available space for the radiation of he'at from the glass in the channel. The raising of the shutters may be continued by turning the handle 42 until radiation of heat from the middle portion ofthe glass in the channel between the members 1 8- and the shutters 25 of that pair is practically unrestricted. The tur-ning of the handle 42 in the opposite direction will permit unwinding of the cables 38 and 39 and the shutters will be lowered until the outer end portions of the arms 37 contact with longitudinally extending stop members 44, thereby preventing the inner ends of the shutters of each pair from `swinging downward below the closed position of 'such shutters, shown in Fig. 2. Thus, the shutters of each pair, may

be opened and closed simultaneously, independently of the remaining shutters, it being understood that an adjusting unit' 41 is provided and suitably connected with each pair of shutters.

The outer side walls 31 of the combustion spaces are provided-intermediate their ends with suitable openings forthe reception of' burner blocks 45, as shown in Figs. 1 and 2. Each of'these burner blockstmay be retained` in place b center an support a burner 47 for projecting a mixture in combustion through the bore of the burner block. The burner is spaced from the bore of the'burner block to permit the ingress ofy more or less air through ports in the plate 46 and through a plate `46' which also serves to" similar ports in a rotary annular valve plate 48 which surrounds the burner blocks. Desirable features of the particular burner and block construction will be .hereinafter described in greater detail as also being included in a corresponding unit at each of the sides of the outer end portion of the forehearth.

The rear side firing spaces 26 are disposed laterally outward from the glass in the forehearth channel. The :flame from the burners 47 into the combustion chambers 26 strike the refractory members 18 and the outer faces of the blocks 21, which are directly in line with the burner nozzles. The blocks 21 have spaces 21a at their lower edges, out of line with the burner nozzle, through which part ofthe flame from the burner may pass. The remainder of the flame from the burner is divided, by reason of its contact with the refractory members 18 and 21, and is distributed both rearwardly and forwardly in the combustion spaces 26, portions thereof being permitted to pass through the spaces between adjacent blocks 19, 20, 21, 22 and 23, beneath the pori tion of the refractory member 18 that is superimposed on such ,supporting blocks. These supporting blocks and the superimposed portion of the member 18 are positioned laterally outward of the glass in the forehearth channel. Thus, the flame from each of the burners 47 is retarded in its movement toward the glass in the fore'- hearth channel. 1 This retardation of the fiame together with the feature of admitting air around the burner and the character of operation of the burner proper, permits the use of liquid fuel without sub]ecting the glass in the forehearth channel to the action of any unconsumed parts of the fuel mixture, practically complete combustion taking place in the combustion space.

The inner portions of each of the refractory members 18 is enlarged downwardly,

as indicated at 18a, toward the side portions of the stream of glass in the forehearth channel, thereby providing bafHe lips and relatively narrow downwardly and inwardly directed passages 181) between the baille lips and the adjacent side walls of the forehearth channel. The flames from the side combustion spaces 24 pass through the spaces l between the supporting blocks 19, 21, 22 and 23 and through the apertures 21a at the lower edges of the block 21 against the downwardly and inwardly ,beveled outer` wa'lls of the lips 18a and are defiected in long, narrow sheets of flame onto the side portions of the glassV stream in the forehearth chan,

nel.

rlhe upper forehearth structure in advance of the conditioning chamber 24-v cooperates 'with the underlying portion of the forehearth 'channel 1 and with the transverse member 15 to provide a second chamber, in-

dicated at 49 in Figs. 1 and 3; The space above the glass in this second chamber is practically separated from the s ace above the glass in the conditioning c amber 24.

by the transverse partition 15. The top of the chamber 49 may be formed of suitable refractory blocks, such as indicated at 50 in Fig. 1, suitably arranged and supported so as to form a transversely arched cover. The

front chamber 49 has open communication v at the central point of the front wall of the feeder bowl, as shown in Fig. 3. The front wall of the upper part of the front chamber 49 comprises atransverse refractory block 52 which preferably has its bottom wall beveled downwardly and forwardly, as indicated at 53, and has side downward extensions or leg portions 54, formed with forwardly and inwardly beveled inner walls 55, wherebyv forwardly moving heated gases and flame from the forward side firing spaces 51 will v be directed both downwardly and forwardly and inwardly and forwardly into the space above the glass inthe feed bowl.

The rear walls of the forward'side firing spaces comprise refractory burner blocks,

each of which preferably comprises an outer refractory member 56, having ya bore consisting of a relatively large circular outer end portion 57 of substantially uniform diu ameter throughout its length, intermediate portion 58 of decreasing rdiameter toward its inner end and of less diameter at its outer end than the 'diameter of the portion p 57 whereby an annular shoulder 59 is provided, and an inner end portion 6() o increasing diameter toward its forward end.

The shoulder 59 and the outer end portion 57 of the refractory member 56 constitutes a seat with which radial fins 61 on the annular inner refractory member 62 of the burner block engage so as to support the latter in concentric relation with the inner walls of the outer member 56. The outer walls of the inner member 62, between the radial fins' 61, taper forwardly as indicated at 63, while the inner walls of the member 62 are curved longitudinally, .as best seen in Fig. 5, so as to provide an inwardly taperin rear end portion 64 and. an outwardly enlarging mainportion 65 of the bore of the member 62, for a purpose to be presently described.

Tl1e,'inner member 62 of the burner block is held in place in the outer member 56 by a.' clamping plate-66, which may be secured l@ with ports 71 corresponding in number, rel` ative arrangement and size with kthe ports 69, whereb more or less air may be admitted throng ports 71-69 and the spaces between the tins 6l to the interior of each of "515 the sidering spaces l or the valve plate 70 may be turned so aste prevent ingress or an, air to the ports 69. The plate66 is provi ed with a central o ening 72, axially aligned with the bore or the inner member 2@ 62 of the burner bloch. A. fuel burner 7 3 is mounted in this opening so that the nozzle ot such burner projects into the bore of the member' 62. The burner 73 may be either a gaseous 4fuel or a liquid fuel burner. The 26 particular burner shown in the drawings is v adapted for the use of liquid fuel and is ot the type disclosed and claimed in the applicants Patent 1,646,703, granted October 25, 1927. A. burner ol this type includes a tutu bular conduit '7d for introducing atomizing air into the annular space between .the fuel tube 7 5 of the burner and the casing of the burner.

A ortion of the clamping plate 66 immett diate y surrounding the burner and inwardly of the annular series of ports 69 is provided with an inner annular series ot ports 76. Each of these ports communicates with the forwardly and inwardly directed annuco lar space between the forwardly projecting tube 7 of the burner nozzle and the portion 64C of the inner wall of the member 62 of the burner bloclr.. A rotary valve 78 is provided with ports 79 corresponding in number, size a and relative arrangement with the ports 7 6.

The arrangement 1s such that the l.valve 78 may be turned about the axis ot the burner to open the ports 76 more or l"less to the at'- limosphere or to completely/'close such ports. so The burner bloclr las a whole is maintained in position at the-rear end of the associate 'lorwardV side `combustion space 5l by the plate 66 and by reason of the lit of the outer member of the burner block with a seat 80 in the adjacent walls ot the'combustion chamber. f

With the arrangement just described, an

atomized mixture of air and liquid -fuel in` combustion will be projected from the burner ti forwardly and inwardly into the cham r 49 and toward or .into the space above thev glass in the feed spout. 'lhe air admitted from the atmosphere through the orts 7 9-7 6 and the bore of the inner' memet er 62 et the burner block` not only will aid' modena in supporting lcombustion so that no unconsumed particles will be projected into contact withlthe glass lut may be utilized to regulate the extent ot forward pro'ection of tlameirom the burnertoward the ront wall ot the eed'spout. Thus, the air through the ports 79-76maylpassrthrough the forwardly and;inwardly'directed` restricted passage at the burner"tipmatv a suicient velocity to cause the dame from the burner tip to projected ilorwmdlyI substantially to. the front wall oli the feeder bowl.

Air tor supporting` combustion alsoimay be admitted through the ports 7l- 69 and the larger spaces atlthe outer side of the inner member 62 ofthe biiier block. Such air will Vjlilow in an V annular stream which will aidcombustion at the forward end4 ot velocity ot the inner annular streama or combustion supportingnair, llhus, 1f it is desired to project the'lilame a'relatively great distance forwardly Jtroni the burner tip, the

valve 7 8 istnrned to admit air through the ports 79--76 llt iti-Vis desired to modify the action of the innerannular stream of cornbustion supporting/'air somewhat, the valve also may be opened to admit the outer more 'sluggish annular stream ot air. Another niode oie operation of the burner would be to closethe inner-valve 78 and to ,open the outer valve 70, thereby shortening the extent ola projection of the dame from the burner and producing a more widely distributed ;dame overtle glass in the stabilizing chamber and in the feed spout. Many combinations of Yadjustments of the two valves 7 0 and 78 wil'lbe useful in controlling the extent of projection of the llame from the burner 73 and the character and distribution of sucli-llame.V

rllhe hereinbetore described burners 47 at the sides of the rear combustion spaces and the burner block-sido, associated therewith, may have substantially the structural features ol the more fully described burner 7 3 .and the inner member 62 o the burner block, the outer series ot ports for the admission of combustion supporting air being omitted. bviously, a, burner and burner bloch assembly, Ysuch as herein described as being applied to` the forward combustion ehamherarnay be employed with each of the rear side combustion chambers.

rllhe front chamber above the glass in the orehearth channel is provided with stacks 8l and 82, respectively,- located at the rear andtorward ends thereof. As best seen in Fig. l, the stack 8l communicates with the rontchamhr 49 directly in front of the rear wall l5 ot the latter while the stack 82 constitutes a forward and upward extension of the cover 14 offthewteeder spout. A. damper 8? is provided for regulating the draft through the stack 81 and. the volume here ` the inner meuibi-fri562V but may not have the of gases permitted to escape therefrom. This damper may be ralsed and lowered by suitable operating means, suck Aas the lever 84, fulcrumed intermediate its lengthat 85 and pivotally connected atone end with the damper 83 and at its other end with an adjusting rod 86. The raising and, lowering of the adjusting rod may be effected by turning an adjusting nut 87 on a threaded portion of the rodl 86, such nut being arranged to bear againstga fixed'member 88 through which the adjusting rod 8 6 extends. The stack 82 also is provided With a damper 89 and with suitable means, not shown, for

' the desired cooling of the middle portion of sired at the time` such stream passes the glass stream during the passage of such stream through the conditioning chamber 24. At the same time,vflame from the burners 47 may be applied to the glass of the side portions of such stream to preventv undue chilling and lagging ofv such side portions of a stream. Preferably, the cooling ofthe middle portion of the stream and the heating or maintenance of temperature of the side portions of the stream are such as to bring the stream throughout practically its entire cross section to the temperature dey from the rear conditioning chamber into the forward stabilizing chamber of the forehearth structure. If this condition has been attained, the flames from fthe burners 7,3 are regulated and controlled as to intensity, eX- tent of projection, and distribution so las to assure equalization of temperatureinv the glass in the stabilizing chamberand in the feed spout and to maintain the temperatureA desired. Obviously, temperature regulating` effects in the front chamber may be produced if required. j L The dampers for the stacks 81-82 may be adjusted with relation to one another to cooperate with the burners toregulably control the distribution of heat throughout the space over the glass in the stabilizing chamber and feed spout and to regulably control draft conditions in the space above the glass forwardly of the transverse partition member 15. y

By closing all the shutters 25, radiation of heat from the middle portion ofthe stream passing from the melting furnace may be reduced to ,a minimumso that the temperature of the glass leaving the melting furnace may be -substantially Lmaintained. Various` effects may be produced by various adjustments of the respective burners and radiation, permitting or preventing shutters, dampers, etc., so as to regulably control the temperature and condition of the` glass to the end that .satisfactory glass will be provided at the place of feedingor'removal.

Preferably, the glass. is brought to the proper temperature and condition at an early point along its path of movement from the melting furnace toward the' placeof feeding or delivery of glass and then equalization and maintenance of. such temperature and condition are effected and maintained in the glass during the remainder of its movement along the forehearth channel and until such glass has been fed through the bottom delivery outlet of the feed spout or otherwise removed'.

Temperature responsive devices, such as thermo-couples, as shown more or less diagrammatically at may be provided in contact with the glass at various places along the length of the forehearth channel and in the feed spout for indicating the temperature of the glass at such places. Such devices lnay be of any suitable known type and` construction. l

While the invention has been described as including features which are particularly adapted for the advantageous use of liquidt fuel burners, heat may be applied by the use of gaseous-fuel burners or other means for applying heat to the glass, such as electric heating elements, maybe used. Also, it is obvious that the features of the invention are susceptible of modification and change from those specifically illustrated and described herein without departing fromthe spirit and scope of the invention.

I claim: i

1. A forehearth comprising a covered channel along which a stream of molten glass may. flow from a melting furnace, means providing a combustion'chambe'r eX- tending along a portion of said' coveredy channel for a substantial, part of the length of the channel, said combustion chamber having communication through a -narrow passage with the space above the glass in said channel, said passage extending the map jor portion of the length ofthe combustion chamber, a burner at the outer side of said chamber for projecting a flame in said combustion 'chamber toward the covered chan'nel and in the general directiony of .said communicating passage,A and baille means inthe path of flame from the burner for diffusing such flame in the combustion chamber along the communicating passage and for preventing projection of flame from the .burner directly into said communicating passage.

2. A forehearth comprising a covered channel I along which a stream of. molten lf'of the channel, said-combustion clia'm er havingv communication through anarrow passage with the space above the lass in said channel, said passage extending the major portion of the length of the combustion chamber, a burner at the outer side ofA said chamber for projecting a flame in said combustion chamber toward the covered channel and in the general direction of said communicating passage, means for. admitting air around said burner into said combustion chamber to promote and support combustion, and baffle means in the path of llame from the burner for diffusing such flame in the combustion chamber along the communicating passage and for preventing projection of flame from the burner directly into said communicating passage.

3. A forehearth comprising achanncl for receiving molten glassv from a melting furnace and for conducting such glass to a place at which glass is to be A'fed or otherwise removed, means providing a conditioning chamber for the glass in a portion of the channel adjacent to the melting furnace, means providing a pair of side combustion chambers extending along the sides of said conditioning chamber, burners for projecting flames into said side combustion chambers, and means located laterally outward beyond the space above the glass is said conditioning chamber for preventing direct projection of said flames onto the glass in the channel and for diffusing such flames in said combustion chambers.

4. A forehearth comprising a channel for receiving molten glass from amelting fur'- nace and for conducting such glass to a place at which glass is to be fed or otherwise removed, means providing a conditioning chamber for the glass in a portion of the channel adjacent to the melting furnace, means providing a temperature equalizing ahd stabilizing chamber for the glass in the outer end portion of said channel, means -controlling temperature and draft conditions l in said equalizing and stabilizing chamber, means providing a pair of side combustion chambers extending along the sides of said conditioning chamber, burners for projecting flames into said side conibustion chambers, and means located laterally outward beyond thespace above tlie glass in said conditioning chamber for preventing direct projection of said flames onto the glass in the channel and for diffusing such flames in said combustion chambers..

5. A foreliearth comprising a channel for receiving molten glass from a melting furnace and for conducting such glassto a place at which glass is to be removed, means- Lacasse the melting furnace, means providing a temperature equalizing and stabilizing chamber above the glass in the outer end portion of said channel, means controlling temperature and draft conditions in said equalizing and stabilizing chamber, means providing a pair of side combustion chambers extending along the sides of said temperature re ulating chamber, `burners for projecting ames into said side combustion chambers, means locatedlaterally outward beyond the space above the glass in said channel for prevent- -ing direct projection of said flames onto the glass in the channel and for diffusing such flame yin said combustion chambers, and

means permitting a regulably controlled radiation of heat from the middle portion of the stream through the top `:of said conditioning chamber.

6. A forehearth comprising a channel for receiving molten glass from a melting furnace and for conducting such glass in a stream to a place at which glass is to be removed, means providing a conditioning chamber over the glass in a portion of the channel adjacent to the wall of the meltingl furnace, means providing a pair of side combustion chambers extending along the sides of said temperature regulating chamber, burners for projecting flames into said side combustion chambers, means located laterally outward beyond the space above the glass in said channel for preventing direct projection of said flames onto the glass inthe channel and for diffusing such flames in said combustion chamber, and

means cooperating with said last named means for directing sheets of fiame from said combustion chambers onto the glass of the side portion of said stream, said sheets of flame extending substantially the entire lengthof the conditioning chamber.

7 In a forehearth structure, a refractory channel for receiving molten glass from a source of supply and along which such glass may flow in a stream, a cover structure for the channel cooperating therewith to provide a conditioning chamber for the glass in a portion of the channel, a combustion space adjacent to the channel communicating with the space above the glass of a side portion of the stream through a narrow passage extending along the. side of said conditioning chamber for the greater part of the length of the chamber, a baffle lip at the inner side of said passage for deflecting heated gases downwardly onto the glass at the adjacent side of said channel, a burner arranged to discharge laterally inward' llO aaa 9 tudinally of said communicating passage, and means for admitting air adjacent to said burner tip to support combustion and to aid in effecting practically complete combustion at a relatively short distancel from said burner tip.

Signed at Hartford, Connecticut, this 18th Y dayof June,1930. ,y l

VERGIL MULHOLLAND.

may flow in a stream, a cover l'structure for the channel and cooperating therewith to provide a conditioning chamber for the '.vlassin a portion of the channel, a comustion space adjacent tov the channel communicating with the space above the glass of a side portion of the stream through al narrow passage extending along the side of said conditioning chamber for the greater part of the length of the chamber, a baille lip at the inner side'of said passage for deflecting heated gases downwardly onto the glass at the adjacent side of said channel, a burner* arranged to. discharge laterally inward through the outer wall of said combustion chamber, said burner being located approximately intermediate the length of the combustion chamber, and baille means extending parallel with said channel for preventing direct projection of flame from said burner into said communicating passage between vthe combustion chamber andthe space above the forehearth channel and for distributing iiame from the burner lon. gitudinally of said communicating passage, said bale meansbeing located laterally outward of the space above the glass in the orehearth channel.

9., .lin a forehearth structure, a refractory channel for receiving molten glass from a source of supply and along which such glass may flow in a stream, a cover structure for -'the channel and coo erating therewith to provide a conditioning chamber for the glass in a portion of the channel, a combastion space adjacent to the channel and communicating with the space above the glass of a side portion of a stream through a narrow passage extending along the side of said conditioning chamber for the greater part of the length of the chamber, a baille lip at the inner side of said passage for deflecting heated gases downwardly onto the glass at the adjacent side of said channel, a burner arranged to discharge laterally in'- ward through the outer wall of said combustion chamber, said burner being located approximately intermediate the length of the combustion chamber, baille means extending parallel with said chamber for preventing direct projection o flame from said' burner inte said communicating passage between the combustion chamber and the space above the forehearth channel and for l distributing flame from the burner longi- 

